Santa Rosa Press Democrat/Zuma, via Corbis

“America has more solar workers than coal miners,” declared a CNN report in late April that summarized a survey done by the Solar Foundation, a nonprofit research and advocacy group. The National Solar Jobs Census, released in November 2012, found that there were 119,016 “solar workers,” meaning employees “who spend at least 50% of their time supporting solar-related activities.”

About 57,000 of workers were engaged in the installation of solar-power equipment, up 9,000 from the year before, while about 30,000 worked in manufacturing, off 8,000 from 2011. All told, solar jobs grew 13.2 percent in 2012 from 2011, and are projected to increase by another 17 percent in 2013.

But are there really more solar employees than coal miners? Well, it depends on which data series you look at. The Solar Foundation’s count comes from a database maintained by a solar-energy trade group, the Solar Energy Industry Association, which it used for a survey of solar employers. The Solar Foundation also sampled other employers, like universities, research labs, and energy companies, that might have some workers engaged in solar-related activities. The figure for coal employees comes from the Bureau of Labor Statistics, whose latest data, based on employer surveys, shows 87,520 coal workers.

There are, however, two other relevant data series. One, from the Energy Information Administration, shows 91,611 coal-mining workers in 2011, a 6.3 percent increase from the year before. A third data set, the most inclusive, maintained by the Mine Health and Safety Administration, reports 143,437 coal-mining employees in 2011 and estimates there were 137,361 in 2012. According to the National Mining Association, which published its own report on mining jobs in 2010, the MHSA data is the most inclusive and best reflects the total number of coal jobs of all the government data sets. Why? It surveys the mines themselves, not the companies, meaning it can capture contract workers who are not necessarily employed by the company that owns or operates the mine.

In any case, there isn’t a great apples-to-apples comparison for coal and solar jobs. If we use the most generous survey of solar jobs and the rough midpoint of government surveys of coal jobs, the two seem to be roughly comparable.

But it’s worth keeping in mind that job creation isn’t the point of energy production? If you were too instead look at energy production from coal and solar, you would see vast, readily apparent differences. According to the most recent data from the EIA, in the last year through February, coal electricity production has clocked in at 1,536,564 gigawatt hours, while all non-hydropower renewable-energy sources, which includes wind, solar, geothermal, and biomass produced 222,407 gigawatt hours. Coal has been responsible for 38 percent of all electricity generation in the last 12 months. (This figure has been consistently falling—coal was 45 percent of all electricity generation in 2010.) According to the EIA, by contrast, solar accounted for a mere .04 percent of electricity generation in 2011. Of course, solar-electricity production is growing rapidly. Since 2007, solar production has increased by at least 28 percent every year.

A lump of coal packs a lot more power than a solar panel, which helps explain why you don’t need that many coal-mining workers to produce such a large amount of electricity. But other factors are in play. Many solar installations are small (say, a couple dozen panels on the roof of a house), and are being put up all over the country in a labor-intensive process. By contrast, coal mines tend to be incredibly large, highly automated operations. Solar’s distributed and growing generating capacity requires a larger job footprint for installers and manufacturers. Meanwhile, much of the infrastructure that supports coal production and distribution—the mines, the train tracks, the trucks, the power plants themselves—has long since been built.

It is clear, however, that coal is not much of a growth business—especially when it comes to electricity production. Research by two Duke professors estimates that 9 percent of all coal plants’ economic viability is threatened by low prices of natural gas, which emits fewer greenhouse gases than coal and is approaching parity in electricity generation. The study also found that 56 percent of coal plants might be threatened by stricter emissions standards.

Although solar is still a small portion of the nation’s energy portfolio, it is one of its fastest-growing components. According to a Federal Energy Regulatory Commission report of the 1,880 megawatts of new installed energy capacity in the first quarter of 2013, 537 megawatts came from solar, 958 from wind, 340 from natural gas, and zero from coal. Solar installers are clearly continuing to hire.

While coal may not be growing much as a source of electricity generation, it still accounts for a huge chunk of the power we consume every day. In January, the most recent month for which data is available, coal accounted for nearly 40 percent of electricity consumed in the U.S. Which is enough to keep coal miners busy.